In general, the detection circuit for use in the memory cell can be used in all the memory devices such as flash EEPROM, EEPROM and EPROM etc. Such detection circuits have a drawback which has to control the threshold voltage of the memory cell to be higher or lower than the threshold voltage in a normal read-out operation, in case they perform a programming or an erasure while they perform a read-out operation having a threshold voltage in a normal read-out operation on the memory cell, and also they lack in reliability because they require an additional identification circuit that distinguishes the state of the memory cell.